1. Field of Invention
The present invention relates to a method for quick connection of a fall arrest anchorage connector to an anchorage. Additionally, the invention relates to a method of providing anchorages that can be pre-cast into concrete structures or attached with a variety of clamps or welding. Additionally this patent relates to anchorage connectors that can be installed and removed remotely and are self indicating if it has been improperly or insufficiently locked into its receiver. Additionally this connector can be used to connect horizontal lifelines to anchorages, install barriers, tie down loads in aircraft and ships and secure aircraft or watercraft to docking ports.
2. Known Art
Remote connect anchorage products are currently used in many applications for fall arrest, rescue, and evacuation situations. Connectors come in a variety of types such as those that are used to open and close locking snap hooks, those that are used to remotely attach to beams and those that connect to remotely attached D-rings. All of these remote connectors can work from extension poles for remotely connecting anchorages or remotely attaching to fallen or disabled workers for rescue. In each case the remote connect/disconnect tool is specifically designed to work with the specified anchorage connector. In each case these remote connectors are made to work with previously installed anchorages, such as D-rings installed overhead or on harnesses, or beam flanges, etc. No system has previously been designed to enable remote connection to concrete structures. This invention relates to, but is not limited to, a method for remote fall protection anchorage connection to poured-in-place concrete structures.
Currently fall protection for workers doing poured in place concrete work is limited to attachment to rebar or concrete forms. When rebar is being erected workers typically tie off to the rebar as it is being erected. When the concrete forms are installed over the rebar, the workers tie off to the concrete forms for fall protection. The problem occurs when the workers are removing the concrete forms. As the forms are removed from the top down, the tie off locations that were once above the worker disappear and the workers only choice is to tie off at his feet unless some other overhead structure exists. In case of a fall this situation creates a 12-ft. free-fall and introduces greater possibility of injury. OSHA requires that systems must be rigged so that a worker will encounter no more than 6-ft. of free-fall. A system has been needed for some time that will solve this problem and enable workers and companies to come into compliance with OSHA requirements. This present invention relates to a method of embedding receivers in concrete form-work with attachment to internal rebar for added pullout strength so that as concrete forms are removed fall arrest anchorage receivers are exposed in the surface of the freshly poured concrete. This will allow the workers to always be attached overhead so that incase of a fall their free-fall is always limited to 6-ft. maximum. Another problem area for concrete work is perimeter fall protection of newly poured floors. OSHA requires that anyone within six feet of the leading edge must have fall protection or there must be a perimeter guardrail. Some work such as glazing requires that the perimeter guardrail be removed. By installing the anchorage receivers in the forms at a distance of six feet from the leading edges and at intervals of approximately eight feet in running length fall arrest attachment points can be installed in the ceiling to provide perimeter fall protection without the need for perimeter guardrails. This receiver can also be used on rooftops or for window washers and in elevator shafts for repairmen. It is also designed for quick connect/disconnect of Horizontal Lifelines. Other uses can be for aircraft tie-downs, boat docks or other applications where high strength flush mounting of anchorages in concrete is required.
The present invention relates to an improved method of installing fall protection anchorages in poured in place concrete that will enable workers to remotely connect and disconnect from their anchorage location. It provides for anchorages that can be flush mounted to walls, roofs, elevator shafts, runways, docks, and other locations that will enable a fall arrest attachment point to always be located above the worker even after forms and scaffolding have been removed. It provides for 5,000-lbs. fall protection for personal fall arrest systems and for 12,000-lbs. anchorages for Horizontal Lifelines. It allows for poured in place anchorage receivers as well as weld-on or clamp on receivers. The present invention allows for anchorage connectors that are light weight, easy to connect and disconnect remotely and have 2 degrees of freedom, (they can both rotate and swivel) to reduce the possibility of rollout with locking and non-locking snap hooks. They can be attached to twin lanyards and moved from workstation to workstation with the user.
The present invention also allows for anchorage connectors that are intended to be installed in the receivers permanently. These connectors use a through bolt installed after the connector is inserted into the receiver. The bolt makes it impossible to separate the connector from the receiver until the bolt is removed. These connectors come in both solid ring and bypass ring styles. The bypass ring is used for HLL application to enable bypassing the anchorage without requiring the worker to disconnect. The solid ring style permanent anchorage connector may be used as an individual permanent fall arrest anchor or as a bypass support for horizontal lifelines.
The method can be used with:
a. A pour in place anchorage receiver for concrete construction.
b. A weld-on or clamp on anchorage receiver for steel erection or in plant use.
c. An anchorage connector that can be connected and disconnects remotely.
d. An anchorage connector that has 2 degrees of freedom to rotate and swivel.
e. An anchorage connector that can be locked into place or removed by a single pushing motion.
f. An anchorage connector that locks using a ball groove mechanism.
g. An anchorage connector that is self-indicating and will push itself out of the receiver if a full lock is not achieved.
h. An anchorage connector that uses 2 or more rows of locking balls and different diameters so that each row of balls can lock only in its designated groove thus assuring that all balls must lock securely for the mechanism to be used.
i. A permanent anchorage connector that may be installed in the receiver and bolted so that it cannot be removed without first removing the bolt. It locks into the ball grooves in the receivers, but does not use locking balls.
j. A permanent anchorage connector that can be used as a manual bypass for horizontal lifeline systems.
k. An improved material and method for manufacturing surface finishing and heat-treating the components.
l. A method for use allowing shock absorbing elements to be attached to the anchorage connector.
m. Special adapters to hold and position the anchorage receiver during installation in floors, ceilings, walls, etc.
In another aspect, this invention relates to the self-indicating fail-safe locking mechanism of the anchorage connector. By pushing in on the center pin of the connector, the ball lock is released and the balls are allowed to move toward the center of the connector thus allowing the connector to be inserted fully into the receiver. The outside diameter of the first row of balls is smaller than the inside diameter of the receiver entry. This assures that the first row of balls in the connector cannot lock into the first ball groove in the receiver. Therefore, for the connector to lock into the receiver each row of balls must be in its designated groove, thus assuring that all balls are sharing an equal load. Should the receiver be damaged and even one of the balls is unable to seat completely in the ball groove, that ball will keep the locking plunger from being able to move underneath any of the balls to lock them into place. In such a case the ejection spring on the end of the connector will push the connector out of the receiver showing that a problem has occurred, that the connector did not properly lock and that this particular receiver should not be used.
In another aspect the manufacturing materials and processes used to produce this product enable it to withstand the severe environment in which it must operate.
Extreme hardness of the surface is required due to its use in an abrasive concrete dust and rock environment. At the same time the surface must be extremely tough, but not brittle, so that it can withstand the shock loads imposed by fall arrest forces. To achieve this combination of toughness and extreme surface hardness a special process has been developed. The material chosen for the receiver is 17-4 PH stainless steel. It is machined in its annealed state at approximately 28 Rc hardness. Once machined, it is polished and then coated with titanium nitride. The nitriding process includeded a 3 hour bake at 700 degrees F., which is the heat treat temperature of 17-4 PH stainless steel. The result of this process is that the 17-4 PH stainless steel is hardened to 40 Rc in its core (which is below the 42 Rc crossover range into brittleness) and yet it is 80 Rc on the surface which is the hardness of titanium nitride. The result is the perfect combination of properties. The receiver is made of corrosion resistant stainless steel (to resist rust in a wet environment), hardened to 40 Rc in its core (which gives it the greatest strength without brittleness) and it is 80 Rc on the surface (which is harder than a file) to give it extreme wear resistance in the highly abrasive environment in which it must operate.